The Use of Mammalian Respiratory Organ Cultures in Rhinovirus C Infection Kin-pong TAO1,2, Louisa LY CHAN1,2, Tiffany TJ LI1, Joseph GS TSUN1, Andrea C SORENSEN 1,3, Taraneh WESTERGERLING1,4, Ting-fan LEUNG1, Renee WY CHAN1,2* 1 Department of Pediatrics; 2 CUHK-UMC Utrecht Joint Research Laboratory of Respiratory Virus & Immunobiology, Faculty of Medicine, The Chinese University of Hong Kong., Hong Kong; 3 Karolinska Institute, Sweden; 4University of Graz, Austria.
Aim of study We aim to establish a rapid and humane option to identify a susceptible animal model for Rhinovirus C (RV-C) study. The identification of an RV-C susceptible animal model would be the initial step to understand the acute infection and the long-term outcomes of RV-C. We hypothesize that the rhinovirus-susceptibility of the respiratory organ explant culture would serve as a reliable predicator for their susceptibility in vivo.
Background Epidemiology evidence indicates that RV-C comprises at least half of the overall RV detected in kids and has a stronger association to childhood asthma exacerbations and is more associated to viremia. However, RV-C is understudied as it does not grow in the standard cell lines and there is not, yet a susceptible model beginning identified.
Methods Respiratory organ explant cultures of neonatal and adult pig and mouse were prepared. The tracheal and alveolar epithelial cultured were inoculated with RV-A of the major and minor group, RV-B and RV-C. The susceptibility of these explant cultures was assessed by viral RNA quantification in the culture supernatant and the tissue lysate. The copy number of the viral gene were monitored for 48 hours post infection and were compared to earlier time points for the validation of virus replication.
Results The Minor group RVs (RV-1B and RV-A2) replicated in the lung explant cultures of both neonatal and adult Balb/c mice, while RV-C only replicated in the lung of neonatal mouse. Major group RV (RV-A16 and RV-B14) replicated in the lung explant cultures of both neonatal and adult pigs. However, RV-C only replicated in the tracheal and lung cultures of neonatal pig. Innate immune response of these explant cultures was measured with RV-C inducing a stronger CXCL10 expression.
Interpretation RV-C can replicate in neonatal mice and pig. The pathogenesis of RV-C can be studied in these two animal models, so that the complete understanding of the innate and adaptive immunity upon its infection can be studied. This explant approach provides scientific evidence in the initial phase to substitute the use of a large number of for live-animals. It serves to refine the experiment setup in vivo.
Acknowledgement This work was supported by the General Research Fund (14101318), CUHK-Direct Grant 2016.077 and 2017.061 and the SURP-2018 program organised by Office of Academic Link-CUHK to RWY Chan.